Stochastic damage evolution modeling in laminates. Ph.D. Thesis
A stochastic mesomechanics model has been developed for damage accumulation analysis in advanced laminated composites. The model is based on a theory of excursions of random process beyond the limiting bounds. Stochastic strains in the laminate subjected to random Gaussian in-plane loading are calculated using lamination theory and random functions theory. Probabilistic variation of stiffness and strength characteristics of plies are used in the analysis. A stochastic version of maximum strain failure criterion is applied for damage probability calculation. A mesovolume concept is utilized in modeling stiffness degradation. The model is verified experimentally based on the available data. Capabilities of the model are illustrated by predictions of damage accumulation and failure in a Kevlar/epoxy (0/ +/- 30/90){sub s} laminate under quasistationary, long-term stationary, and cyclic loading. Effects of loading rate, deviation, stationary level and cyclic amplitude on damage evolution are discussed. High-cycle fatigue behavior of laminate is calculated utilizing the observed stages in failure accumulation under the cyclic loading. Percolation type analysis of damage morphology is performed for the inhomogeneous anisotropic media. The model and computer codes developed can be incorporated into structural analysis software and used in design of laminated structures.
- Research Organization:
- Bipel International, Inc., Trumbull, CT (United States)
- OSTI ID:
- 218162
- Report Number(s):
- N-96-21379; NIPS-96-34619; TRN: 9621379
- Resource Relation:
- Other Information: TH: Ph.D. Thesis; PBD: Jan 1994
- Country of Publication:
- United States
- Language:
- English
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